A specific and ultrasensitive chemiluminescent sandwich ELISA test for the detection and quantitation of pneumolysin

J Immunoassay Immunochem. 2001;22(2):99-112. doi: 10.1081/IAS-100103223.


A chemiluminescent sandwich ELISA test has been developed for the detection and quantitation of pneumolysin. The test is based on a mouse monoclonal as the capture antibody and on rabbit polyclonal IgGs as detection antibodies, in combination with an anti-rabbit IgG alkaline phosphatase conjugate. The estimated detection limit of the purified recombinant toxin in phosphate-buffered saline with 0.05% Triton X-100 is around 5 pg ml(-1), with averaged intra- and inter-assay variation coefficients of 7% and 13.5%, respectively. The assay has been applied to the quantitation of pneumolysin in pneumococcal isolates, providing, for the first time, a direct measurement of the amount of the toxin produced by different strains, a variation has been found in their pneumolysin content. The test is highly specific as no other purified toxins or human pneumonia- or meningitis-associated bacteria yielded false-positive results. This specific and highly sensitive method could help in the diagnosis of human infections.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacterial Proteins
  • Enzyme-Linked Immunosorbent Assay / methods*
  • Humans
  • Luminescent Measurements
  • Recombinant Proteins / analysis
  • Sensitivity and Specificity
  • Streptolysins / analysis*
  • Streptolysins / blood


  • Bacterial Proteins
  • Recombinant Proteins
  • Streptolysins
  • plY protein, Streptococcus pneumoniae